1. Field of the Invention
The present invention relates to a liquid ejecting device, particularly to a liquid ejecting device used for an inkjet printer or an apparatus for coating liquid material.
2. Description of the Related Art
As an image recording apparatus for recording an image on a recording medium such as a paper sheet, the inkjet printer is generally known. In the inkjet printer, the liquid ejecting device for ejecting the ink is mounted. This liquid ejecting device is provided with recording heads for ejecting the ink from a plurality of nozzles and a drive circuit for driving the recording heads.
Herein, in the recording heads, for ejecting the ink from each of a plurality of nozzles, actuators which are deformed corresponding to each nozzle, are provided. The actuator is connected to the drive circuit, and swelled/expanded and contracted based on the waveform of a drive signal inputted from this drive circuit, and ejects the ink from the nozzle. Hereupon, in the liquid ejecting device, an RC filter circuit is formed of a resistance such as a FFC (Flexible Flat Cable) which is a transmission path of the drive signal, and a capacitance of the driven actuator. Therefore, when a drive signal is transmitted from the drive circuit to the actuator, the high frequency component of the drive signal is lost through the RC filter circuit. As the result, there is a possibility that the drive signal of the waveform optimized for the driver is not transmitted to the actuator. Particularly, when a number of actuator arrangements are increasing, a deformation of a shape of the each drive signal waveform is becoming unacceptable.
In order to solve this problem, recently, a drive circuit in which an individual power amplifier is provided for each of head units instead of a common amplifier, and by which the drive signal of the drive waveform generation circuit is supplied to a plurality of power amplifiers and a plurality of head units are driven, is developed (for example, Tokkai No. 2000-325882). Hereby, a total of the capacitance of the actuator which is driven by one power amplifier is divided and becomes small, and the time constant (π=RC) itself can be made small. As smaller the time constant is, the input waveform and the output waveform of the drive signal to the RC filter become almost the same shape. Accordingly, a loss of the high frequency component through the transmission path can be reduced, and the waveform of the applied drive signal can be transmitted to the actuator as it is. Then, when this drive circuit is used, the actuator can be driven without the waveform of the applied drive signal being so much changed. As the result, an ejected drop speed or an ink amount of the ink drop ejected from each nozzle can be stabilized and equalized.
Hereupon, as described above, in the case where the actuator which is deformed corresponding to each nozzle, is provided, when the ink is ejected from each nozzle, there is a case where the vibration of the actuator wall influences the ejected drop speed from the adjoining nozzle. FIG. 9 represents the drop speeds V1, V2, V3, V4, V5, V6 of each of nozzles when the ink is simultaneously ejected from a plurality of nozzles, and the drop speed V7 when the ink is ejected from a single nozzle. As can be clearly seen also from FIG. 9, in the ejected drop speed V3 when simultaneously ejected from a plurality of nozzles, and the ejected drop speed V7 when the ink is ejected from a single nozzle, although the ejection is conducted from the same nozzle, the ejected drop speed is not equal. Like this, the phenomenon that the ejected drop speed is different in a case where the ink is simultaneously ejected from a plurality of nozzles, and in a case where the ink is ejected from a single nozzle, is called cross-talk. Further, as an index expressing a degree of the cross-talk, there is a cross-talk amount. The cross-talk amount is, when considered being aimed to one nozzle (aimed nozzle), in a ratio of the ejected drop speed (the drive speed of a plurality of nozzles) of the aimed nozzle when the ink are simultaneously ejected from a plurality of nozzles, and the ejected drop speed (the drive speed of a single nozzle) of the aimed nozzle when the ink is ejected from only an aimed nozzle, expressed by “the cross-talk amount=((the drive speed of a plurality of nozzles)/(the drive speed of a single nozzle)−1)×100 (%)”.
When the absolute value of the cress-talk amount is closer to 0%, it is shown that the speed difference between the time of a plurality of nozzle drive, and the time of a single nozzle drive, is small. That is, when the absolute value of the cress-talk amount is large, because the speed difference between the time of a plurality of nozzle drive, and the time of a single nozzle drive is large, a dislocation of the impact position of the ink drop on a media is generated by the difference of the ejecting pattern, and the possibility that the image quality is lowered, is high.
Particularly, when the drive circuit written in the Tokkai No. 2000-325882 is applied, the waveform of the applied drive signal is transmitted to the actuator as it is. As the result, the rising and falling edge of the waveform become sharp and deform channel wall rapidly, and the vibration of the channel is easily transmitted to the adjoining channel. Particularly, there is a problem that the sharp deformation of the channel wall increases the ejected drop speed from the adjoining nozzle. That is, the influence which affects the adjoining nozzle meniscus, becomes large, and as the result, it becomes a factor that the absolute value of the cross-talk amount between adjoining nozzles is increased.